3beta-aminoandrost-5-ene-17beta-carboxylic acid and derivatives thereof



United States Patent 3,246,018 3/3-AMlNOANDROST-5-ENE-17B-CARBOXYLICACID AND DERIVATIVES THEREOF Leslie A. Freiherg, Waulregan, and JohnWayne Cole, Deerfield, Ill., assignors to Abbott Laboratories, NorthChicago, Ill., a corporation of Illinois No Drawing. Filed June 10,1964, Ser. No. 374,160 11 Claims. (Cl. 260-397.1)

The present invention relates to new steroids; more particularly, itrelates to 3(3-aminoandrost-5-ene-17/5- carboxylic acid and thecorresponding alkyl esters and N-substituted derivatives.

The new steroids are represented by the general formula COOR" wherein Ris hydrogen, loweralkyl or a fatty acid acyl group and wherein R" and R"are hydrogen or loweralkyl. The new compounds are usefulgrowth-regulating agents; particularly, they influence the growth of thethyroid gland in warm-blooded animals. The new steroids also possessanti-androgenic activity of the type described by Dorfman in ActaEndocrinologica, volume 33, page 308 (1960). Furthermore, they may beused as intermediates in the synthesis of alkaloids of the holarrhenaseries which have useful properties as described in Theta-pie, volume15, page 1212 (1960), as local anesthetics and muscle relaxants. Forsuch synthesis, the present amino acids are treated in the form of theiramido esters with methyl Grignard reagent to form. the intermediate20-tertiary alcohol, which is then transformed into the 20-ketone by themethod described by Koechlin and Reichstein in Helv. Chim. Acta, volume27, page 549 (1944).

The new compounds are made by reacting a 6-alkoxy- 17/3-carbalkoxy 3a,5acycloandrostane with hydrazoic acid in an inert, anhydrous, non-polar,organic solvent such as benzene, toluene, xylene, tetrahydrofurane,pentane, and the like, in the presence of an acid catalyst such as borontrifluoride, toluene sulfonic acid, and the like. When boron trifluorideis used, it may be bubbled into the reaction mixture or it may be addedin the form of, a solid complex such as the etherate.

The formed compound, 3;? azidoandrost -ene-175- carboxylic acid ester isseparated from the reaction mixture and converted to the 3B-aminoderivative by reduc-' tion. The reaction for making the 3B-azidocompound can be carried out at room temperature with satisfactoryresults, although temperature as high as 40 C. may be used where fasterconversion is desired. The reaction of the hydrazoic acid with the6,17-disubstituted cycloandrostane is preferably allowed to proceed forat least 1 hour. The reduction of the 3-azido ester to the corresponding3-amino compound can be done in various ways known in the art, e.g., bytreating the azido com pound with zinc and acetic acid, by hydrogenatingthe azido compound using a mild catalyst or even by electrolyticreduction.

The obtained 3/3-amino compounds can be converted into the analogousacylamino or alkylamino derivatives through methods well accepted in theart, e.g., a 3fi-acylamino compound is obtained by treating the aminocom- 3,246,018 Patented Apr. 12, 1966 ICC pound with an acyl chloride ora fatty acid anhydride; the alkylated derivatives can be made, e.g., byfirst making a Schiif base with an aliphatic aldehyde and subsequentlypartially hydrogenating the latter, using Raney nickel catalyst. The3fi-alkylamino compound so obtained may be converted into itsN-alkyl-N-acyl derivative by treatment with an acyl chloride or a fattyacid anhydride.

It will be apparent to those skilled in the art that the above esterscan easily be saponified to the corresponding 17,8-carboxy derivativesand the carboxy derivatives can be esterified, in turn, with any desiredloweralkyl alcohol to the corresponding alkyl esters.

To illustrate the preparation of the new compounds of the presentinvention, reference is made to the following examples which are notintended to limit the invention in any respect. In these examples,wherever reference is made to a mixture of solvents and no ratio of suchsolvents is given, it is to be understood that the first named solventis used to dissolve the material to make a concentrated solution, andthe second solvent is then added to induce or complete crystallization.

Example 1 .6B-m ethoxy-I 7fi-carb0mefhoxy-3 ot,5acycloandrosfane Amixture of 11.0 grams of 3fl-p-toluenesulfonoxy-17fl-carboxymethoxy-androst-5-ene, 22 grams of anhydrous soduim acetate,and 1.0 liter of anhydrous methanol is refluxed with stirring for 6hours. About twothirds of the methanol is then distilled and 1.0 literof water is added. The product is extracted with ether and the etherwashed in turn with 10% sodium hydroxide and water. The ether extract isdried with anhydrous magnesium sulfate and evaporated, giving 7.31 gramsof crude 6B methoxy-17fiearbomethoxy-3a,5a-cycloandrostane. Purificationis accomplished by absorption onto 250 grams of magnesium silicate,activated as described in US. 2,393,625 (marketed under the trade nameof Florisil). Elution is begun with benzene and followed bybenzene/ether. The major consecutive fractions are combined andevaporated, leaving 5.82 grams of 6,8- methoxy-17B-carbomethoxy-3u,5acycloandrostane with a melting point of 7074 C. A small samplecrystallized from methanol/water shows a melting point of 72.5- 73.5 C.The analytical values for this sample show excellent agreement with thevalues calculated for the compound of the empirical formula C H OExample 2.-3fl-azido-1 7(3-carbomethoxyandrost-S-ene To 3.1 grams of6,8-methoxy-17fl-carbomethoxy-3a,5acycloandrostane is added 65 ml. ofbenzene containing 4.0 grams of hydrazoic acid, and 2.0 ml. of freshlydistilled boron trifluoride etherate. The mixture is allowed to stand at25 for 3.5 hours. To the reaction mixture, ml. of 6 N ammonium hydroxideis added, followed by the addition of 200 ml. of ethyl ether. Theorganic phase is washed in turn with 6 N ammonium hydroxide and water.The organic layer is dried with magnesium sulfate and then evaporated,giving 3.18 grams of 3B- azido--carbomethoxyandrost-S-ene melting at99-105 C. A small sample crystallized from methanol/water has a meltingpoint of 106l08 C. The analytical values obtained are in close agreementwith those calculated for the compound of empirical formula C H N OExample 3.-3,8-amino-I7B-carbomethoxyandr0st-5-ene and N-alkylderivatives (a) To a rapidly stirred solution of 6.95 grams of 3B-azido-17fi-carbomethoxyandrost-S -ene in 490 ml. of glacial aceticacid/ethyl ether 1:1) is added 37 grams of acidwashed electrolytic zincsponge. The mixture is stirred overnight at 25 C. and the zinc is thenremoved by filpotassium hydroxide and water.

3 tration. The acetic acid used for rinsing the zinc is combined withthe filtrate. The ether in the filtrate is removed by evaporation andmost of the acetic acid is distilled in vacuo. To the residue isadded amixture of 100 ml. of Water and 100 of ethyl ether. The mixture is madebasic with 30% aqueous potassium hydroxide and the aqueous phase isseparated and extracted with ethyl ether.

The combined ether extracts are washed in turn with The ether is driedwith anhydrous magnesium sulfate and evaporated, giving 5.10 grams ofcrude 3 B-arnino-17B-carbomethoxyandrost-S-ene. Purification isaccomplished by absorption of a solution of this crude material in 20ml. of benzene on a column containing 250 grams of Florisil and elutingthe column with benzene/piperidine (100013) followed by gradient elutionwith benzene/ ethyl ether/piperidine (1000 :2013). The major consecutivefractions are combined, treated with charcoal, and evaporated, to give2.28 grams of 3B- amino-l7fi-car1bomethoxyandrost-5-ene melting at 145-151 C. A small sample is crystallized from rnethanol/ lwater, giving apure product melting at 1505-1515 C. and having an analysis in closeagreement with the values calculated for the formula C H NO (b) Asolution of 50 mg. of 3fi-amino-l7p-carbomethoxyandrost-S-ene, 20 ml. ofethanol, and mg. of acetaldehyde is hydrogenated in a Parr shaker afteradding 9 mg. of Nancy nickel at room temperature and atmosphericpressure. After absorption of one molar equivalent of hydrogen, themixture is filtered and evaporated. From the residue, 3B-et-hylamino 175catrbomethoxyandrost-S-ene is obtained, of which an analytical sampleshows good agreement with the values calculated for the compound offormula C H NO Alternatively the Schiff base resulting from the abovereaction with acetaldehyde may be reduced directly with sodiumborohydride in methanol solution at room temperature.

(c) A solution of 200 mg. of 3fi-amino-17B-carbomethoxyandrost-S-ene in25 ml. of methanol containing 0.1 ml. of concentrated hydrochloric acidis stirred with excess formaldehyde and zinc dust according to theprocess of Wagner as described in Organic Reactions, 4, page 198 (1 948,John Wiley & Sons). The crude dimethylamino ester solution isevaporated, cooled, and then shaken with ether and cold dilute sodiumhydroxide to separate an ether solution of the product. The ethersolution is washed with sodium hydroxide solution, followed by water,and then concentrated to give theSB-dimethylaminol75-carbomethoxyandrost-S-ene of the formula 2a a7 2Example 4.3fl-amin0-17,8-carb0xyandrost-5-ene To a solution of 1.56grams of 3/i-amino-17fl-carbothethoxyandrost-S-ene in 40ml. of methanolis added 10 ml. of water containing 0.9 gram of potassium hydroxide.After refluxing the mixture overnight, it is cooled, filtered, and themethanol is removed in vacuum. A small amount of methanol is then .addedagain to redissolve the precipitate and the solution is neutralized with1.0 N hydrochloric acid. The crystals of 3Bamino-l7fi-earboxyandrost-S-ene are collected and dried at 60 C. and 1.0mm. pressure; they represent 1.31 grams of crude- 3,8-amino-17B-carboxyandrost-5-ene. Purification of these crystals is elfected bysublimation at 250260 C./0.l mm; pres sure, giving crystals with amelting point of 443'446 C. (decomposition) in a sealed evacuatedcapillary. The analytical values obtained .are in close agreement withthose calculated for the formula C H NO Example5.3fi-acetamido-17fl-carb0metlz0xyandrost-S-ene 7 To a solution of 677mg. of 3/3-amino-17B-carbomethoxyandrost-S-ene in 30 ml. of pyridine isadded 16ml. of acetic anhydride and the mixture is allowed to'stand atroom temperature overnight. The reaction mixture is 4 then poured ontoice and the product is extracted with ether. The ether extracts arewashed with 3 N hydrrochloric acid, 10% sodium hydroxide, and finallywith water. The ether is dried with anhydrous magnesium sulfate and isevaporated, giving 709 mg. of crude 3,8-acetamidocarbomethoxyandrost-S-ene. Recrystallization from methanol/Water andsubsequently from benzene/ hexane gives 341 mg. of the pure productmelting at 2134-9136 C. in a sealed evacuated capillary. Analyticalvalues obtained are in close agreement with those calculated for thecompound of empirical formula C H NO By replacing the above aceticanhydride with propionic anhydride, the corresponding 3,8-propionamideis obtained in a similar yield.

When 3B-ethylamino-17B-carbomethoxyandrost-S-ene is used in the aboveprocedure in place of the Eli-amino compound, the product obtained is3fi-N-ethyl-N-acetylamino-17B-carbomethoxyandrost-5-ene, having theformula C25H39NO3.

Example 6,-3B-acetamia'o-17f3-carboxyandr0st-5-ene To a solution of 350mg. of SB-amino-Uficariboxyandrost-S-ene in 12 ml. of pyridine is added10 ml. of acetic anhydride and the mixture is allowed to stand overnightat room temperature. The reaction mixture is then poured onto crackedice and the product is dissolved in chloro form and washed in turn with3 N hydrochloric acid and water. The chloroform solution is dried withanhydrous magnesium sulfate and evaporated to give crude3fi-acetamido-17fl-carboxyandrost-5-ene which is recrystallized frommethanol to give 251 mg. of 3fl-acetamido-l7p-carboxyandrost-5-enemelting at 282-285 C. in a sealed evacuated capillary. The analyticalvalues are in close agreement with those calculated for the formula Itwill be apparent to those skilled in the art that other derivativesfalling within the above-defined class of new compounds can be made inanalogous processes. For instance, all the3,8-loweralkylamino-l7l3-carboxyandrost- S-enes and their alkyl esterscan be made from the corresponding Sfl-amino compound by following theprocedure outlined above and that described in Organic Reactions, volumeIV, page 196 ff. (John Wiley & Company, 1948). Similarly, other3,8-acylarnino derivatives can be made by using lon ger fatty acid.anhydrides or halides in the reaction with the 3 ,B-amino compoundsdefined above.

The 3,8-azido compounds are best prepared by treating the6,8-alkoxy-l7fi-carbomethoxy-3a,5u cycloandrostanes with fborontrifluoride and hydrazoic acid. The boron can be used as a gas or as acomplex such as the trifluoride etherate. Other acid catalysts may beused similarly.

Others may practice the invention in any of the numerous ways which willbe suggested to those skilled in the art by the present disclosure. Allsuch practice of the invention is considered a part hereof, provided itfalls within the scope of the appended claims.

We claim:

1. The process of making 3fi-amino-17/3-ca-rbalkoxyandrost-S-enesconsisting essentially in exposing a 6-alkoxyl7p-carbalkoxy-3a,5a-cycloandrostane to hyd'razoic acid in the presence of a non-polar,inert, anhydrous, organic solvent and an acid catalyst, separating theformed 3/3- azido-17,8-carba1koxyandrost-S-ene, and reducing the 3/3-azido group in the latter to the Sit-amino group.

2. The process of claim 1 wherein said acid catalyst is borontrifluoride.

3. The process of claim 2 wherein said boron trifluoride is added in theform of the etherate complex.

4. The process of claim 1 wherein said organic solvent is benzene.

5. The process of claim 1 wherein said 1713-carbalkoxy group is thecarbomethoxy group.

6. A steroid of the formula from the group consisting of hydrogen and A,A being 0 0 OR lower alkyl.

| 7. 3,8-amino-17,8-carbomethoxyandrost-S-ene. 8.3,6-amino-17fi-carboxyandrost-5-ene.

5 9. 3B-ethy1amino-I7 8-carbomethoxyandrost-S-ene. 10.3fi-aeet-amido-17fi-carbomethoxyandrost-5-ene. l 11' 33-acetamido-17B-carboxyand-rost-S-ene.

No references cited. 10 wherein R is selected from the group consistingof hydro- LEWIS GOTTS Pnmary Examiner gen, A and ACO, and wherein R andR" are selected HENRY A. FRENCH, Assistant Examiner.

6. A STEROID OF THE FORMULA